Make plaintext export more compatible with SMS Backup and Restore

This commit adds the contact name and the readable date (and time) to
the plaintext export of every message. That's because that is how SMS
Backup and Restore does it, so this commit makes Signal more compatible.

Closes #6452
// FREEBIE

src/org/thoughtcrime/securesms/database/PlaintextBackupExporter.java

@@ -45,6 +45,7 @@ public class PlaintextBackupExporter {
       while ((record = reader.getNext()) != null) {
         XmlBackup.XmlBackupItem item =
             new XmlBackup.XmlBackupItem(0, record.getIndividualRecipient().getNumber(),
+                                        record.getIndividualRecipient().getName(),
                                         record.getDateReceived(),
                                         MmsSmsColumns.Types.translateToSystemBaseType(record.getType()),
                                         null, record.getDisplayBody().toString(), null,

src/org/thoughtcrime/securesms/database/XmlBackup.java

@@ -11,6 +11,7 @@ import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileWriter;
 import java.io.IOException;
+import java.text.SimpleDateFormat;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -18,7 +19,9 @@ public class XmlBackup {
 
   private static final String PROTOCOL       = "protocol";
   private static final String ADDRESS        = "address";
+  private static final String CONTACT_NAME   = "contact_name";
   private static final String DATE           = "date";
+  private static final String READABLE_DATE  = "readable_date";
   private static final String TYPE           = "type";
   private static final String SUBJECT        = "subject";
   private static final String BODY           = "body";
@@ -29,6 +32,8 @@ public class XmlBackup {
   private static final String SC_TOA         = "sc_toa";
   private static final String LOCKED         = "locked";
 
+  private static final SimpleDateFormat dateFormatter = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z");
+
   private final XmlPullParser parser;
 
   public XmlBackup(String path) throws XmlPullParserException, FileNotFoundException {
@@ -62,7 +67,9 @@ public class XmlBackup {
 
         if      (attributeName.equals(PROTOCOL      )) item.protocol      = Integer.parseInt(parser.getAttributeValue(i));
         else if (attributeName.equals(ADDRESS       )) item.address       = parser.getAttributeValue(i);
+        else if (attributeName.equals(CONTACT_NAME  )) item.contactName   = parser.getAttributeValue(i);
         else if (attributeName.equals(DATE          )) item.date          = Long.parseLong(parser.getAttributeValue(i));
+        else if (attributeName.equals(READABLE_DATE )) item.readableDate  = parser.getAttributeValue(i);
         else if (attributeName.equals(TYPE          )) item.type          = Integer.parseInt(parser.getAttributeValue(i));
         else if (attributeName.equals(SUBJECT       )) item.subject       = parser.getAttributeValue(i);
         else if (attributeName.equals(BODY          )) item.body          = parser.getAttributeValue(i);
@@ -80,7 +87,9 @@ public class XmlBackup {
   public static class XmlBackupItem {
     private int    protocol;
     private String address;
+    private String contactName;
     private long   date;
+    private String readableDate;
     private int    type;
     private String subject;
     private String body;
@@ -90,12 +99,14 @@ public class XmlBackup {
 
     public XmlBackupItem() {}
 
-    public XmlBackupItem(int protocol, String address, long date, int type, String subject,
-                         String body, String serviceCenter, int read, int status)
+    public XmlBackupItem(int protocol, String address, String contactName, long date, int type,
+                         String subject, String body, String serviceCenter, int read, int status)
     {
       this.protocol      = protocol;
       this.address       = address;
+      this.contactName   = contactName;
       this.date          = date;
+      this.readableDate  = dateFormatter.format(date);
       this.type          = type;
       this.subject       = subject;
       this.body          = body;
@@ -112,10 +123,18 @@ public class XmlBackup {
       return address;
     }
 
+    public String getContactName() {
+      return contactName;
+    }
+
     public long getDate() {
       return date;
     }
 
+    public String getReadableDate() {
+      return readableDate;
+    }
+
     public int getType() {
       return type;
     }
@@ -172,7 +191,9 @@ public class XmlBackup {
       stringBuilder.append(OPEN_TAG_SMS);
       appendAttribute(stringBuilder, PROTOCOL, item.getProtocol());
       appendAttribute(stringBuilder, ADDRESS, escapeXML(item.getAddress()));
+      appendAttribute(stringBuilder, CONTACT_NAME, item.getContactName());
       appendAttribute(stringBuilder, DATE, item.getDate());
+      appendAttribute(stringBuilder, READABLE_DATE, item.getReadableDate());
       appendAttribute(stringBuilder, TYPE, item.getType());
       appendAttribute(stringBuilder, SUBJECT, escapeXML(item.getSubject()));
       appendAttribute(stringBuilder, BODY, escapeXML(item.getBody()));